Low-temperature laser texturing device and method for improving shape quality of surface texture production

Abstract

A low-temperature laser texturing device and method for improving the shape quality of surface texture production are disclosed. The laser texturing device may include: a laser oscillator that generates a laser toward a texturing target; a target receiving portion that can receive the texturing target; and a cooling portion that is integrally formed with or separately from the target receiving portion and can cool the texturing target received in the target receiving portion.

Description

Technology Field

[0001] The present invention relates to a low-temperature laser texturing method and apparatus for improving the shape quality of a surface texture produced using laser texturing equipment. Background Technology

[0002] Functionally applying textures to the surfaces of mechanical parts used in automobiles, robots, and the like is a significant technical challenge. Textures formed on the surface serve to enhance lubrication by supplying lubricant to the contact surface during frictional motion under lubricated conditions, or to capture wear particles generated during the friction process. This improves the performance and lifespan of mechanical parts and can significantly reduce maintenance costs. For example, applying textures to the surface of an automobile engine cylinder improves the lubrication performance of the piston-cylinder system and effectively captures wear particles generated at the contact surface, thereby extending the lifespan of the part. Furthermore, since this can be applied to high-tech fields such as flexible and wearable devices, as well as transparent displays, it is expected to enhance product durability.

[0003] Methods for creating textures on a surface include physical machining and chemical etching. While physical machining methods such as milling and stamping allow for the creation of textures over a large area in a short time, resulting in lower production costs, it is not possible to produce fine textures of approximately 50 μm depending on the method. Additionally, burrs may form around the texture, leading to reduced shape precision and degraded quality. On the other hand, chemical etching allows for the achievement of very high texture shape quality, but it has the disadvantage of significantly increasing costs due to the long production time required.

[0004] Recently, laser texturing technology has been developed as a method to compensate for these advantages and disadvantages and is being utilized by various institutions. Lasers can produce textures over a large area in a short time of tens of seconds and can form fine textures of several micrometers in size compared to conventional physical processing methods such as milling or stamping. However, when using a laser, burrs may form around the texture during the process where the surface at the irradiated point melts and then re-solidifies, which can lead to a problem where the shape quality deteriorates compared to textures produced by chemical etching.

[0005] While precise machining is essential for applying textures to the surfaces of machine parts, industrial applications require the ability to efficiently apply them over large areas while maintaining uniform quality. Conventional mechanical machining methods can secure a certain level of precision but have limitations in forming fine textures and pose a risk of reduced uniformity during large-area processing. Chemical etching methods offer high precision but come with issues such as long processing times and increased costs. Therefore, there is a need for a machining technology that can form uniform textures within a short time while reducing manufacturing costs, thereby contributing to the improvement of machine part performance across various industrial sectors. Prior art literature

[0006] Registered Patent No. 1027108650000 The problem to be solved

[0007] The problem that this invention aims to solve is to provide a technology capable of reducing processing time and costs while forming a texture of uniform quality on the surface of machine parts. To this end, a non-contact processing method utilizing a laser is applied, but it is necessary to minimize the problem of burr formation caused by the limitations of conventional laser texturing. Furthermore, this invention proposes a method to improve surface processing characteristics by optimizing laser parameters and adjusting cooling conditions to maintain consistent quality even during large-area processing. Through this, the applicability in various industrial fields such as automobiles, machine tools, and electronic devices is enhanced, and it can contribute to improving the performance and durability of machine parts.

[0008] The present invention was developed to overcome the limitations of existing technology and aims to provide a method and apparatus for producing textures capable of producing fine textures with a size of 10 to 500 μm and a maximum depth of 100 μm, while maintaining uniform quality even over a large area. The focus is on improving the uniformity and shape precision of the produced textures, as well as increasing processing speed to enable large-area texturing in a short time. In particular, the present invention aims to enable efficient manufacturing by implementing a process capable of forming a uniform texture over a large area of ​​at least 10 x 10 cm within a maximum of 10 minutes. means of solving the problem

[0009] In one aspect, the present invention provides an apparatus for performing laser texturing on a texturing target.

[0010] In one embodiment, the laser texturing device may include: a laser oscillator that generates a laser toward the texturing target; a target receiving portion in which the texturing target can be received; and a cooling portion formed integrally with or separately from the target receiving portion and capable of cooling the texturing target received in the target receiving portion.

[0011] In one embodiment, the cooling unit can cool the texturing target to about -20°C or lower.

[0012] In one embodiment, the cooling unit can cool the texturing target to about -40 to -20 ℃.

[0013] In one embodiment, the laser texturing device may further include a focusing lens that focuses a laser irradiated from the laser oscillator.

[0014] In one embodiment, the laser oscillator can generate a laser with an output of about 2 to 6 W.

[0015] In one embodiment, the laser oscillator can generate a laser at a frequency of about 3 to 8 kHz.

[0016] In one embodiment, the laser texturing can form a micro-sized texture.

[0017] In one embodiment, the micro-sized texture may be about 10 to 500 μm.

[0018] In one embodiment, the micro-sized texture may be about 150 to 250 μm.

[0019] In another aspect, the present invention provides a method for performing laser texturing on a texturing target.

[0020] In one embodiment, the laser texturing method may include: a first step of cooling the texturing target and maintaining the cooled state; and a second step of generating a laser through a laser oscillator toward the texturing target to perform laser texturing.

[0021] In one embodiment, the cooling of the first step can be performed to a temperature of about -20°C or lower.

[0022] In one embodiment, the laser oscillator can generate a laser with an output of about 2 to 6 W.

[0023] In one embodiment, the laser oscillator can generate a laser at a frequency of about 3 to 8 kHz.

[0024] In one embodiment, the laser texturing can form a micro-sized texture.

[0025] In one embodiment, the micro-sized texture may be about 10 to 500 μm.

[0026] In one embodiment, the micro-sized texture can be formed to a size of about 150 to 250 μm.

[0027] In another aspect, the present invention provides a machine part.

[0028] In one embodiment, the machine part may have a texture formed on its surface by performing laser texturing on the surface through a laser texturing method according to the embodiment of the present invention described above.

[0029] In one embodiment, the texture formed on the machine part may have a size of about 10 to 500 μm.

[0030] In one embodiment, the texture formed on the machine part may have a size of about 150 to 250 μm.

[0031] In one embodiment, the burr height of each texture may be about 30 μm or less.

[0032] In one embodiment, the burr height of each texture may be about 15 to 30 μm.

[0033] In one embodiment, the laser texturing device can adjust the wavelength of the laser according to the surface material of the texturing target, and can use a laser with a wavelength of about 1024 nm for metal materials and a laser with a wavelength of about 248 nm for polymer materials.

[0034] In one embodiment, the cooling unit may be operated by a circulation method of a cooling medium, and the cooling medium may include liquid nitrogen, cooling water, and cooling gas.

[0035] In one embodiment, the cooling portion may be cooled using a Peltier element, and the Peltier element may perform cooling by directly contacting the target receiving portion or through a separate heat-conducting member.

[0036] In one embodiment, the laser texturing device may use a multi-pulse laser method to precisely control the shape of the texture, and may finely adjust the depth of the texture by adjusting the duration and interval of each pulse.

[0037] In one embodiment, the laser texturing device may include an adjustment mechanism capable of adjusting the irradiation angle of the laser to maintain the shape of the texture uniformly, thereby forming a texture of a specific pattern.

[0038] In one embodiment, the texturing method may undergo at least 100 laser irradiation processes for the same location, and the uniformity of the texture may be improved through repeated processing.

[0039] In one embodiment, the texturing method can control the scanning speed of a laser to control the size and depth of the texture, and the density and depth of the texture can be determined according to the scanning speed.

[0040] In one embodiment, the texture formed on the surface of the machine part may have a specific pattern and may include circular, hexagonal, linear patterns, etc.

[0041] In one embodiment, the texture of the machine part may be arranged in a specific arrangement to reduce friction and improve the lubrication effect, and may be designed to increase the retention of the lubricant.

[0042] In one embodiment, the texture of the machine part can impart hydrophobic or hydrophilic surface characteristics by adjusting the contact angle of the surface, and can provide condensation control or anti-contamination functions.

[0043] In one embodiment, the machine part may undergo a separate post-processing step after texture formation, and the post-processing step may include chemical etching, oxidation treatment, plasma treatment, etc.

[0044] In another embodiment, the low-temperature laser texturing device of the present invention comprises a laser head unit including a laser oscillator and a laser focusing lens, a controller capable of adjusting the position of the head unit, and a bottom plate unit for fixing a sample. The bottom plate unit includes a fixing clamp to secure the sample so that it does not move during processing, and is characterized by being equipped with a low-temperature plate capable of lowering the temperature of the sample surface to a sub-zero level. This helps to minimize thermal deformation that may occur during processing and to form a more uniform texture. Effects of the invention

[0045] The advantage of the present invention lies in its ability to help produce more precise textures while reducing shape non-uniformity and burr formation that may occur in conventional laser texturing methods. Furthermore, by performing laser processing in a low-temperature environment, thermal deformation of the surface can be minimized, and texture uniformity can be improved. Through this, it can contribute to improving the performance and durability of mechanical parts in various industrial fields, such as automotive parts, machine tools, and electronic devices, and is also expected to shorten processing time and reduce manufacturing costs compared to conventional processing methods.

[0046] Compared to textures produced using conventional laser texturing techniques, the fine-sized textures produced by the present invention can improve shape uniformity, such as size and depth, during large-area processing. Additionally, they can help reduce the formation of burrs around the texture that may occur during the processing process. The low-temperature laser texturing device and method of the present invention can be expected to reduce production costs compared to conventional texture production methods that require long processing times, and can contribute to improving the performance and lifespan of applied machine parts by enhancing texture quality. This can also have a positive impact on reducing maintenance costs. The present invention can be utilized throughout the machinery industry, such as in bearings, piston-cylinder systems, and machine tool components. Its scope of application is wide, as it can also be applied to fields requiring high durability, such as flexible / wearable devices, or to transparent displays where both optical properties and durability are important. Brief explanation of the drawing

[0047] FIG. 1 is a perspective view of a low-temperature environment laser texturing device according to the present invention. FIG. 2 is an example of a texture produced using low-temperature laser texturing according to the present invention. Figure 3 shows the result of texturing a steel surface under room temperature and 6 W laser power conditions. Figure 4 shows the result of texturing a steel surface under room temperature and 2 W laser power conditions. Figure 5 is the result of a texture shape obtained by performing texturing on a steel surface according to the present invention under low temperature and 6 W laser power conditions. Figure 6 is the result of a texture shape obtained by performing texturing on a steel surface according to the present invention under low temperature and 2 W laser power conditions. Specific details for implementing the invention

[0048] Hereinafter, embodiments of the present invention will be described in detail with reference to the attached drawings. Since the present invention is susceptible to various modifications and may take various forms, specific embodiments are illustrated in the drawings and described in detail in the text. However, this is not intended to limit the present invention to the specific disclosed forms, and it should be understood that it includes all modifications, equivalents, and substitutions that fall within the spirit and scope of the present invention. Similar reference numerals have been used for similar components in the description of each drawing. In the attached drawings, the dimensions of the structures are shown enlarged compared to the actual dimensions for the clarity of the present invention.

[0049] The terms used in this application are used merely to describe specific embodiments and are not intended to limit the invention. Singular expressions include plural expressions unless the context clearly indicates otherwise. In this application, terms such as “comprising” or “having” are intended to specify the presence of the features, numbers, steps, actions, components, or combinations thereof described in the specification, and should be understood as not precluding the existence or addition of one or more other features, numbers, steps, actions, components, or combinations thereof. In the context of this specification, terms such as “about” may mean about ± 1%, about ± 2%, about ± 3%, about ± 4%, about ± 5%, about ± 6%, about ± 7%, about ± 8%, about ± 9%, or about ± 10% of the figures described in the specification.

[0050] In addition, the description of one aspect of the present invention may be applied identically or similarly to the description of other aspects for identical or similar configurations or terms.

[0051] Unless otherwise defined, all terms used herein, including technical or scientific terms, have the same meaning as generally understood by those skilled in the art to which the present invention pertains. Terms such as those defined in commonly used dictionaries should be interpreted as having a meaning consistent with their meaning in the context of the relevant technology, and should not be interpreted in an ideal or overly formal sense unless explicitly defined in this application.

[0052] In one aspect, the present invention provides an apparatus for performing laser texturing on a texturing target. In the context of this specification, the term laser texturing includes a process of forming a fine pattern on the surface of a material using a laser. This process involves finely processing the surface using the high energy of a laser beam, and since it is a non-contact method, mechanical damage can be minimized. Furthermore, by adjusting laser parameters, the size, depth, spacing, etc., of the texture can be controlled, which can help meet various functional requirements.

[0053] The laser texturing technology applied in this invention goes beyond simply engraving patterns on a surface and can be utilized to improve mechanical performance or impart specific functions. For example, optimizing the shape and arrangement of the texture can be expected to control friction or improve lubrication characteristics. Additionally, specific optical properties can be realized, allowing for applications in display or sensor technologies. Performing laser texturing in a low-temperature environment can contribute to reducing thermal deformation during processing and maintain the quality of the processed surface more uniformly.

[0054] In one embodiment, the laser texturing device may include: a laser oscillator that generates a laser toward the texturing target; a target receiving portion in which the texturing target can be received; and a cooling portion formed integrally with or separately from the target receiving portion and capable of cooling the texturing target received in the target receiving portion.

[0055] The role of the laser oscillator described above is to form fine patterns by irradiating a laser beam onto the surface to be textured. The laser can process textures by emitting a focused beam of high energy to locally heat, evaporate, melt, or deform the material surface. This reduces contact-induced damage compared to conventional mechanical processing methods and enables more precise texturing. Furthermore, by adjusting the laser output, wavelength, and frequency, the depth, size, and shape of the texture can be varied, which helps in producing surface patterns suitable for various applications.

[0056] The role of the aforementioned object receiving unit is to support and fix the texturing object so that it remains stable even during processing. Since high energy is concentrated on the surface during the laser texturing process, the uniformity of the texture may deteriorate if the object shakes or moves even slightly. To prevent this, the object receiving unit may include a robust fixing device and may be adjustable to accommodate materials of various sizes and shapes. Additionally, depending on the structural characteristics of the object receiving unit, it may perform functions such as optimizing the incident angle of the laser beam or effectively discharging byproducts generated during processing.

[0057] The role of the cooling unit is to control the temperature of the texturing target to minimize thermal deformation that may occur during processing. If high-temperature energy is concentrated during the laser texturing process, the surface may overheat locally, potentially leading to unwanted material deformation or quality degradation. To prevent this, the cooling unit can perform the function of maintaining the target surface at a constant temperature using a cooling medium or a thermoelectric element. In particular, in the low-temperature laser texturing method applied in the present invention, the cooling unit can help improve the uniformity of the shape and reduce the formation of burrs around the texture by maintaining the target temperature at a sub-zero level.

[0058] In one embodiment, the cooling unit may cool the texturing target to about -20°C or lower. In one embodiment, the cooling unit may cool the texturing target to about -40°C to -20°C.

[0059] The advantage of performing laser texturing on a cooled object lies in the fact that it can help minimize thermal deformation that may occur during processing and improve the precision of the texture shape. When high energy is concentrated on the surface during laser processing, repeated local thermal expansion and contraction can occur, potentially leading to unexpected shape distortion or non-uniform patterns. However, performing processing in a cooled state allows the surface temperature to be maintained stably, thereby suppressing thermal expansion and consequently improving the uniformity of the texture. Furthermore, the rapid thermal solidification process can be controlled, reducing the formation of burrs that commonly occur around textures, and it can also contribute to minimizing thermal damage such as surface oxidation or microcracks.

[0060] In one embodiment, the laser texturing device may further include a focusing lens that focuses the laser irradiated from the laser oscillator. The role of the focusing lens is to gather the laser beam irradiated from the laser oscillator into a single focus, thereby enabling more precise texturing. If the laser beam is irradiated without focusing, there is a possibility that the processing area will be wide or the energy will not be transmitted uniformly. In contrast, by focusing the laser beam using a focusing lens, high energy can be maintained at a specific focus, making it possible to precisely control the size and depth of the texture.

[0061] In one embodiment, the laser oscillator can generate a laser with an output of about 2 to 6 W.

[0062] If the laser oscillator output is excessively low, insufficient laser energy may be delivered, potentially preventing the material surface from being processed to the desired depth. This can lead to incomplete texture formation, leaving only minute deformations on the surface, or causing processing to occur only in certain areas. In particular, for materials with relatively high thermal resistance, such as metals, low output can significantly reduce processing speed because the laser fails to deliver sufficient energy.

[0063] If the laser oscillator output is excessively high, there is a possibility that unwanted thermal deformation may occur as excessive heat is transferred to the surface of the workpiece. If excessive laser energy is transferred, the texture depth may be inconsistent, or the uniformity of the shape may be reduced as the surface melts and solidifies abnormally. In addition, the surface may overheat due to high output, leading to the excessive formation of burrs, or the surrounding area may be affected, resulting in the formation of fine cracks or oxide layers.

[0064] In one embodiment, the laser oscillator can generate a laser at a frequency of about 3 to 8 kHz.

[0065] If the laser oscillator frequency is excessively low, the number of laser pulses irradiated per unit time decreases, potentially leading to a reduction in processing speed. Since laser texturing processes a surface by repeatedly irradiating a laser beam at regular intervals, a lower frequency may result in more time required to process the same area. Furthermore, if the interval between laser pulses becomes too long, the surface may not be processed continuously, potentially leading to a decrease in texture uniformity. This can result in incomplete texture pattern formation or failure to achieve the desired depth in specific areas.

[0066] If the laser oscillator frequency is excessively high, the number of laser pulses irradiated per unit time increases, potentially leading to a rise in the amount of laser energy overlapping within the same area. This can result in the surface becoming overheated, or molten material in the irradiated area failing to be sufficiently removed and re-solidifying, leading to uneven shape. Furthermore, if the energy of individual pulses is reduced due to the excessively high frequency, there is a possibility that the material may not be processed to the desired depth, or that fine deformations may remain only on the surface, resulting in insufficient processing effectiveness.

[0067] In one embodiment, the laser texturing can form a micro-sized texture. In one embodiment, the micro-sized texture may be about 10 to 500 μm. In one embodiment, the micro-sized texture may be about 150 to 250 μm.

[0068] If the texture size is excessively small, there is a possibility that the functional effects of the surface may not be fully realized. Generally, textures perform roles such as trapping wear particles, but if the size is too small, these functions may not operate properly. For example, on a surface designed to maximize lubrication, if the texture is too small, lubricant may not be stored sufficiently, potentially reducing friction. Furthermore, from a manufacturing perspective, excessively small textures require precise patterns, which can lead to longer processing times and make it difficult to maintain a uniform shape.

[0069] If the texture size is excessively large, the mechanical stability of the surface may be compromised, potentially leading to performance degradation in certain applications. For example, if a texture intended to control friction is too large, lubrication performance may be reduced.

[0070] In one embodiment, the laser texturing device may further include a clamp for fixing the texturing target.

[0071] In another aspect, the present invention provides a method for performing laser texturing on a texturing target.

[0072] In one embodiment, the laser texturing method may include: a first step of cooling the texturing target and maintaining the cooled state; and a second step of generating a laser through a laser oscillator toward the texturing target to perform laser texturing.

[0073] The role of the first step described above is to lower the surface temperature of the texturing target to minimize thermal deformation that may occur during the laser processing process. Since laser texturing is a method of processing by irradiating a surface with a high-energy laser beam, there is a possibility that the target material may expand or deform as it heats up locally. Such thermal expansion can degrade the uniformity of the texture and result in inconsistent shapes of the processed pattern. However, performing cooling in advance allows the surface temperature to be maintained stably, suppressing rapid thermal deformation and helping to improve the precision of the texture. Additionally, in a cooled state, the molten material generated after laser irradiation can solidify rapidly, potentially reducing excessive material solidification or burr formation on the surface.

[0074] The role of the second step described above is to form a desired texture by irradiating a laser while the material is cooled, thereby realizing a uniform texture pattern and maintaining processing quality. By delivering precise energy to the surface using a laser oscillator, fine patterns can be formed, and the size and depth of the texture can be optimized by adjusting conditions such as laser output, frequency, and irradiation time. In particular, if laser texturing is performed while the material is cooled, thermal deformation is reduced, which is expected to enhance the uniformity of the processed texture and minimize surface damage. Furthermore, as the surface material solidifies rapidly after laser irradiation, there is a possibility that the material's microstructure will remain stable, which can be advantageous for maintaining precision even when processing specific patterns repeatedly.

[0075] In one embodiment, the cooling of the first step may be performed to a temperature of about -20°C or lower. In one embodiment, the laser oscillator may generate a laser with an output of about 2 to 6 W. In one embodiment, the laser oscillator may generate a laser at a frequency of about 3 to 8 kHz.

[0076] In one embodiment, the laser texturing can form a micro-sized texture. In one embodiment, the micro-sized texture may be about 10 to 500 μm. In one embodiment, the micro-sized texture may be formed with a size of about 150 to 250 μm.

[0077] In another aspect, the present invention provides a mechanical part. In the present invention, a mechanical part may refer to a part having a texture formed on its surface to impart specific mechanical, physical, or functional characteristics, and may perform roles such as controlling friction, improving lubrication performance, dispersing surface stress, and controlling surface thermal energy. Such a part can be applied not only to industrial machinery such as bearings, piston-cylinder systems, and machine tool elements, but also to various products requiring precise surface treatment, such as wearable devices, optical components, and electronic devices. In particular, textures formed through a low-temperature laser texturing technique have a higher likelihood of maintaining uniform quality compared to conventional mechanical processing or chemical etching methods, and can contribute to maximizing functionality without performance degradation.

[0078] Meanwhile, applications that are laser-textured by a laser texturing device according to an embodiment of the present invention or laser-textured by a laser texturing method according to an embodiment of the present invention are not limited to mechanical parts, and other non-limiting examples are also included in the term "mechanical parts." These non-limiting examples include semiconductor wafers, display panels, solar panels, optical lenses, camera sensor protective glass, smartphone displays, touch panel substrates, wearable sensors, electronic device heatsinks, hard disk platters, microfluidic chips, biosensor substrates, fuel cell electrodes, battery electrodes, micro-robot components, MEMS (Micro-Electro-Mechanical Systems) structures, semiconductor packaging substrates, medical implant surfaces, dental crowns and implants, artificial joint surfaces, vascular stents, microneedle patches, contact lenses, fiber optic connectors, laser reflectors, light guide plates (LGPs), aircraft fuselage panels, turbine blade surfaces, micropatterned films for water and dust resistance, automotive headlamp covers, sensor protective films, functional coating films, flexible electronic devices, RFID tag substrates, sound filters and acoustic control panels, micro-speaker diaphragms, micro-LED substrates, e-paper displays, bulletproof glass surfaces, anti-counterfeiting holographic patterns, laser-marked medical tools, smart glass, superhydrophobic coated surfaces, dust resistance, and Examples include antistatic films, microfluidic channel surfaces, electromagnetic shielding films, metal 3D printed structures, automotive exhaust gas filters, optoelectronic device electrodes, and electric vehicle battery cooling panels.

[0079] In one embodiment, the mechanical part may have a texture formed on its surface by performing laser texturing on the surface through the laser texturing method according to the embodiment of the present invention described above. The advantage of a part with such a textured surface is that it can improve mechanical performance through various functional enhancements. First, when a precise texture is formed on the surface, friction performance control can be improved through enhanced lubrication performance, which can help reduce frictional wear between mechanical parts and increase durability. In particular, for dynamic parts such as bearings or piston-cylinder systems, the texture can increase the retention of lubricant, thereby reducing energy loss due to friction and enabling stable operation over a long period.

[0080] Furthermore, applying specific patterns can improve the heat dissipation performance of components, which can help enhance the performance stability of electronic devices where heat dissipation is critical or components used in high-temperature environments. Microstructures generated through laser texturing can also control surface wettability, making them useful in applications requiring waterproof or superhydrophobic performance. Additionally, optimizing surface roughness allows for effective application in industries requiring increased adhesion; for instance, it can be used to strengthen the bonding of coating materials or improve the bonding strength between specific materials.

[0081] In one embodiment, the texture formed on the machine part may have a size of approximately 10 to 500 μm. In one embodiment, the texture formed on the machine part may have a size of approximately 150 to 250 μm. If the size of the texture is excessively small, there is a possibility that surface functionality may not be sufficiently expressed. To expect effects such as friction control, improved lubrication performance, and stress distribution, the texture must maintain a certain proportion; however, if the proportion is too small, the contact area with the surface is not sufficiently secured, making it difficult to achieve the desired performance. For example, when applying a texture for the purpose of improving lubrication performance, if the size is excessively small, the lubricant may not be sufficiently retained on the surface, potentially reducing the friction reduction effect. Furthermore, as the texture becomes smaller, precise machining is required during the manufacturing process, which may lead to longer laser texturing times and reduced productivity. If the size of the texture is excessively large, it may lead to increased friction due to reduced lubrication performance, and the texture may wear out due to stress concentration at the edges under specific load conditions, making it difficult to maintain the performance of the texture.

[0082] In one embodiment, the burr height of each texture may be about 30 μm or less. In one embodiment, the burr height of each texture may be about 15 to 30 μm. In the context of this specification, the term "burr" may refer to a protrusion or irregular residual structure formed on a surface during the laser texturing process. During laser processing, due to high-energy irradiation, the material may locally melt or evaporate, leaving behind fine protruding structures around the processing area. Such burrs can alter the shape of the texture or reduce surface uniformity, and may require additional polishing or post-processing in subsequent processes. Furthermore, when precise textures are required to impart specific functionality, the formation of unexpected burrs may impair functional performance.

[0083] Lower burr levels increase the likelihood of maintaining uniform texture quality and reduce the need for additional post-processing. In particular, when textures are applied for friction control or lubrication performance enhancement, excessive burr formation can lead to uneven contact areas or unexpected increases in friction. Furthermore, in applications where surface precision is critical, such as electronic components or optical devices, the presence of burrs can degrade functional performance and impair bonding or adhesion between components. Therefore, it may be necessary to control laser irradiation conditions to minimize unnecessary melting or material residue, and applying specific cooling conditions can help suppress burr formation.

[0084] In one embodiment, the laser texturing device can adjust the wavelength of the laser according to the surface material of the texturing target, and can use a laser with a wavelength of about 1024 nm for metal materials and a laser with a wavelength of about 248 nm for polymer materials.

[0085] The reason laser wavelengths must be selected differently depending on the surface material is that each material absorbs light of a specific wavelength to varying degrees. In laser texturing, the efficiency and quality of the process can vary depending on how effectively the surface absorbs laser light and how that energy is transferred to the material. Generally, metallic materials effectively absorb relatively long-wavelength lasers, whereas polymer materials tend to absorb short-wavelength lasers better. Failure to select an appropriate wavelength may result in insufficient laser energy being transferred to the surface or cause unnecessary thermal damage.

[0086] If the laser wavelength is excessively short compared to the appropriate wavelength, the laser light may be absorbed too strongly by the surface, potentially causing the material to heat up rapidly. This can result in deeper processing than expected or cause parts of the surface to evaporate abnormally, making it difficult to form a uniform texture. In particular, materials with high thermal conductivity, such as metals, may develop microcracks due to localized overheating, while plastics or polymer materials may experience surface carbonization or discoloration. Additionally, as high energy is concentrated in a narrow area, the formation of unwanted burrs may increase, and there is a possibility that the fine structure of the surface may be damaged.

[0087] If the laser wavelength is excessively long compared to the appropriate wavelength, there is a possibility that the laser light will not be sufficiently absorbed by the surface and will be largely reflected or transmitted. This can reduce processing efficiency and make it difficult to obtain textures of the desired depth and shape. In particular, for polymer materials, long-wavelength lasers may be transmitted without being absorbed, leaving only fine traces on the surface without forming any substantial texture. In the case of metals, increased surface reflection may prevent the uniform transmission of laser energy, which can cause variations in texture depth.

[0088] In one embodiment, the cooling unit may operate by a cooling medium circulation method. The advantage of this method is that the cooling effect can be maintained uniformly by continuously circulating the cooling medium. Since heat is continuously applied to the surface during the laser texturing process, a method of continuously removing heat by circulating the cooling medium may be more effective than a method in which cooling occurs only temporarily. This allows the surface temperature of the texturing target to be maintained at a constant level and helps reduce thermal shock or surface deformation caused by sudden temperature changes. Furthermore, the cooling medium circulation method can effectively control the temperature without reducing the processing speed, which may be advantageous for maintaining productivity.

[0089] In one embodiment, the cooling medium may include liquid nitrogen, cooling water, and cooling gas. Non-limiting examples of other possible cooling media include liquid helium, liquid hydrogen, liquid ammonia, liquid carbon dioxide, ethanol cooling liquid, methanol cooling liquid, propylene glycol cooling liquid, ethylene glycol cooling liquid, fluorinated carbon cooling liquid, perfluorocarbon cooling liquid, silicone oil cooling liquid, acetone cooling liquid, liquid Freon, liquid air, liquid argon, liquid krypton, liquid neon, hydrofluoric acid cooling liquid, sodium cooling liquid, potassium cooling liquid, caustic soda cooling liquid, supercritical carbon dioxide, liquid methane, hydrocarbon cooling liquid, acetic acid cooling liquid, nitrogen-helium mixed cooling liquid, liquid bromine, liquid nitrogen-oxygen mixed cooling liquid, polymer-based cooling fluid, organosilicon cooling fluid, etc.

[0090] In one embodiment, the cooling unit may be cooled using a Peltier element. In this specification, a Peltier element refers to a cooling device utilizing the thermoelectric effect, which absorbs heat from one side and releases it from the other side by passing an electric current through a junction composed of two types of semiconductor materials. Since the temperature can be rapidly controlled solely by electrical control, miniaturization and precise temperature control are possible without a complex cooling system.

[0091] The above Peltier element can perform cooling by directly contacting the target receiving portion or through a separate heat-conducting member. The advantage of this method is that it can simultaneously improve cooling efficiency and processing precision. When the Peltier element is in direct contact with the target receiving portion, the surface temperature can be rapidly lowered, resulting in a fast thermal response speed. This allows for immediate control of localized temperature rises occurring during laser processing, which helps minimize thermal deformation. On the other hand, when using a separate heat-conducting member, the Peltier element does not need to be in direct contact with the sensitive surface, thereby reducing the risk of damage due to material properties. Additionally, it is possible to expand the cooling area or selectively cool only specific parts by adjusting the size and shape of the heat-conducting member.

[0092] In one embodiment, the laser texturing device may use a multi-pulse laser method to precisely control the shape of the texture, and may finely adjust the depth of the texture by adjusting the duration and interval of each pulse.

[0093] The multi-pulse laser method refers to a technique that irradiates multiple laser pulses sequentially over short periods, rather than using a single continuous laser. This method can help improve the precision of surface processing by controlling the energy of each pulse and is advantageous for forming textures of specific shapes more uniformly. By adjusting the interval and duration between individual pulses, heat accumulation in the material can be reduced compared to irradiating the same energy all at once, thereby minimizing thermal deformation or microcracks. Furthermore, applying the multi-pulse method allows for fine control of depth and shape, making it useful for repeatedly forming desired texture patterns.

[0094] In one embodiment, the laser oscillator may include a feedback control system capable of automatically adjusting the laser intensity, and can measure the shape of the texture in real time during processing and adjust the laser output accordingly. Through the feedback control system, the processing status of the surface can be monitored in real time during the laser texturing process, and the laser output can be automatically adjusted accordingly. Generally, laser processing may result in a texture being formed deeper or shallower than expected due to the reflectivity of the material, thermal conductivity characteristics, and surface changes occurring during processing. When the feedback control system is applied, the laser intensity can be finely adjusted as needed while continuously measuring the depth, shape, and surface uniformity of the texture using a sensor, thereby helping to achieve a more precise texture.

[0095] In one embodiment, the laser texturing device may include an adjustment mechanism capable of adjusting the laser irradiation angle to maintain a uniform shape of the texture, thereby enabling the formation of a texture of a specific pattern. By adjusting the laser irradiation angle, the shape of the texture can be maintained more uniformly, and it can help to precisely implement a specific pattern. Generally, since laser texturing is a method of forming a desired pattern by directly irradiating a laser onto a surface, if the irradiation angle is fixed, there is a possibility that the texture depth and shape may not be uniform depending on the curvature or slope of the surface being processed. In particular, for parts with curved surfaces or complex shapes, if the laser is irradiated only at a fixed angle, processing may be excessive or insufficient in some areas. To prevent this, dynamically adjusting the laser irradiation angle allows for maintaining optimal irradiation conditions tailored to the geometric shape of the surface, thereby contributing to the formation of a uniform texture.

[0096] In one embodiment, the texturing method may undergo at least 100 laser irradiation processes for the same location, and the uniformity of the texture can be improved through repetitive processing. The number of times does not limit the scope of the present invention, and the number of laser irradiations can be adjusted according to the desired depth of the texture, shape precision, material properties of the processing target, and heat accumulation effects. Generally, repetitive laser irradiation may be required as the depth of the texture increases or as a precise shape is required, which can help to balance the material removal rate and thermal effects.

[0097] In one embodiment, the texturing method may control the scanning speed of the laser to adjust the size and depth of the texture, and the density and depth of the texture may be determined according to the scanning speed. If the scanning speed is increased, the time the laser is irradiated per unit area is reduced, which may result in lower energy delivered to the surface. This may lead to a shallower texture depth and a lower density of the processed pattern. While a fast scanning speed may be advantageous for reducing processing time, if sufficient energy is not delivered to the surface, the texture may be incompletely formed or it may be difficult to maintain a uniform pattern. If the scanning speed is decreased, the time the laser stays per unit area increases, which may increase the energy delivered to the surface. This may result in a greater texture depth and the formation of a clearer pattern. Additionally, at a low scanning speed, the same pattern can be engraved more precisely, which may be advantageous for improving the uniformity of the texture. However, if the laser is irradiated at the same location for a long time, heat accumulation may occur, potentially causing the surface to overheat or unexpected thermal deformation.

[0098] In one embodiment, the texture formed on the surface of the machine part may have a specific pattern and may include circular, hexagonal, linear patterns, etc. Non-limiting examples of other possible patterns include triangular patterns, square patterns, rectangular patterns, rhombus patterns, elliptical patterns, irregular dot patterns, spiral patterns, grid patterns, wavy patterns, stepped patterns, radial patterns, striped patterns, checkerboard patterns, honeycomb patterns, cross patterns, star patterns, porous structure patterns, microgrooves, pyramidal patterns, complex polygonal patterns, orthogonal grid patterns, circular dot patterns, directional determination patterns, fabric weave patterns, dot matrix patterns, arch patterns, metasurface patterns, asymmetric microstructure patterns, contour patterns, superhydrophobic surface patterns, etc. These various patterns can be utilized to impart various functionalities to the machine part, such as controlling friction, relieving surface stress, improving heat dissipation, and optimizing fluid flow.

[0099] In one embodiment, the texture of the machine part may be arranged in a specific arrangement to reduce friction and enhance lubrication effects, and may be designed to increase the retention of the lubricant. Examples of such designs may include patterns and arrangements optimized to ensure that the lubricant is uniformly distributed and retained on the surface. For example, a regular circular pattern arrangement can help reduce friction by effectively retaining the lubricant on the friction contact surface, while a hexagonal honeycomb pattern may be advantageous for forming a uniform lubricating film over a large area. Additionally, a linear groove pattern can guide the flow of the lubricant in a specific direction, helping it to be evenly distributed across the entire surface.

[0100] In one embodiment, the texture of the machine part may impart hydrophobic or hydrophilic surface characteristics by adjusting the contact angle of the surface, and may provide condensation control or anti-contamination functions. Examples of methods for imparting hydrophobic or hydrophilic surface characteristics may include adjusting the microstructure of the surface or applying specific chemical treatments.

[0101] In one embodiment, the machine part may undergo a separate post-processing step after texture formation, and the post-processing step may include chemical etching, oxidation treatment, plasma treatment, etc.

[0102] Chemical etching refers to a process that selectively removes unwanted parts from the surface of machine parts using specific chemical solutions. This process can help adjust fine surface roughness or improve texture uniformity by removing impurities generated during processing. Generally, strong acid or base solutions are used to dissolve specific areas of the material, and it can be utilized to finely adjust the depth or shape of the texture. In particular, for metallic materials such as stainless steel or titanium, desired surface characteristics can be achieved by controlling the corrosion rate, while for materials such as polymers or glass, it can be applied to adjust surface hydrophilicity or adhesion.

[0103] Oxidation treatment refers to a method of oxidizing the surface of mechanical parts under specific conditions to form a protective film or impart specific functions. This process can be useful for improving the corrosion resistance of metal surfaces and for imparting hydrophobic or hydrophilic properties by controlling surface energy. For example, in the case of aluminum, anodizing can increase surface strength and improve durability, while materials such as iron or titanium can increase heat resistance and wear resistance through the formation of an oxide film.

[0104] Plasma treatment refers to a process of modifying the surface of mechanical parts using high-energy ions or activated gases. This process can finely adjust surface roughness or control hydrophilicity or hydrophobicity by inducing specific chemical reactions. Since plasma treatment enables precise surface modification without the use of chemical solutions, it can be considered an environmentally friendly process.

[0105] Other non-limiting examples of post-processing processes include electrolytic polishing, laser annealing, ion beam treatment, flame polishing, nanocoating, ultrasonic cleaning, heat treatment, chemical vapor deposition (CVD), physical vapor deposition (PVD), mechanical polishing, high-temperature carburization, low-temperature nitriding, electroplating, optical coating, hydrophobic coating, anti-reflective coating, thin film formation, metal deposition, electron beam treatment, organosilicon coating, fluorination, laser surface modification, basic solution treatment, thermal oxidation, supercritical fluid treatment, micro-arc oxidation, anodic oxidation, and nanoporous structure formation.

[0106] The embodiments of the present invention are described below. However, the embodiments described below are merely partial embodiments of the present invention, and the scope of the present invention is not limited to the following embodiments.

[0107] The present invention is a technology that utilizes a laser texturing technique in a low-temperature environment to produce high-quality textures over a large area on the surface of a steel material within a very short time of up to tens of seconds.

[0108] The device of the present invention is composed of a laser head unit that irradiates a sample with a laser and a lower plate unit that can fix the sample to be textured. The laser head unit may be composed of a laser oscillator (1) that generates a laser and a focusing lens (2) that focuses the laser to a single point. Additionally, the lower plate unit may be composed of a low-temperature plate (4) and a clamp (5) that can firmly fix the sample (3) during texture processing. The laser head unit may be configured to allow for vertical and horizontal movement and to allow for height adjustment. When processing a surface texture using a laser, the laser oscillator (1) may be configured with a different wavelength range of the laser depending on the material.

[0109] For example, when processing a texture on the surface of a steel material, a laser oscillator (1) with a wavelength of 1024 nm can be configured, and when processing a texture on the surface of a polymer material, a laser oscillator (1) with a wavelength of 248 nm can be configured. The low-temperature plate (4) of the lower plate portion, which is the core idea of ​​the present invention, can be configured to lower the temperature of the sample surface to a sub-zero level. Below, the texture quality effect according to an example and a comparative example of texture production using a low-temperature laser texturing device according to the present invention is described. Table 1 shows the results of analyzing the texture shapes of the example and comparative example according to laser texturing at low temperature and room temperature.

[0110] division Texture size (μm) Texture depth (μm) Burr height (μm) Comparative Example 1 202 80 40 Comparative Example 2 Unmeasurable Unmeasurable 30 Example 1 199 75 30 Example 2 197 30 15

[0111] The texture fabrication process of the example was carried out through a sample cooling process and a texturing process in which a laser was irradiated onto the surface. As shown in Fig. 3, to fabricate a fine, discontinuous texture, the sample was fixed to the bottom plate using a clamp, and then subjected to a cooling process for approximately 15 minutes to lower the sample surface temperature to minus 20°C. After cooling to a certain level and confirming that the sample surface temperature was maintained for about 3 minutes, the laser texturing process was performed. The texture size was set to 200 μm, and the laser texturing process was carried out by setting the texture depth to 30-80 μm depending on the laser power.

[0112] [Example 1] After the sample surface was cooled to a sub-zero temperature, laser texturing was performed with the laser power set to 6 W, the frequency to 5 kHz, and the number of processing cycles for each texture set to 100. The total processing time was 2 minutes, and the results of the surface shape analysis after texturing are illustrated in Figure 5.

[0113] [Example 2] After the sample surface was cooled to a sub-zero temperature, laser texturing was performed by setting the laser power to 2 W, the frequency to 5 kHz, and the number of processing cycles for each texture to 500. Compared to Example 1, the laser texturing process was carried out by lowering the laser power while increasing the number of processing cycles. The total processing time was 10 minutes, and the results of the surface shape analysis after texturing are illustrated in Figure 6.

[0114] [Comparative Example 1] Texturing was performed under the same conditions as the laser texturing conditions of Example 1, at room temperature without cooling the sample. The total processing time was 2 minutes, the same as in Example 1, and the results of the surface shape analysis after texturing are shown in Fig. 3.

[0115] [Comparative Example 2] Laser texturing was performed under room temperature conditions without cooling the sample, with the laser power set to 2 W, the frequency to 5 kHz, and the number of processing cycles for each texture set to 100. The total processing time was 2 minutes, and the results of the surface shape analysis after texturing are illustrated in Fig. 4. When evaluating texture quality based on indicators such as texture size, depth, and burr height, the experimental examples can be judged to have superior texture quality as they reduced the burr height compared to the comparative example.

[0116] FIG. 1 is a perspective view of a low-temperature environment laser texturing device according to the present invention. Referring to FIG. 1, it can be seen that a laser generated from a laser oscillator (1) passes through a focusing lens (2) and is irradiated onto a texturing target (3). The texturing target (3) is placed on a target receiving portion, and a plurality of holes of a certain pattern are formed on its surface. During this process, while the surface is processed using a laser, a cooling portion (5) can perform the role of controlling the temperature of the texturing target (3). The target receiving portion (4) serves to stably fix the texturing target and, in conjunction with the cooling portion (5), can function to maintain a constant temperature during processing. Through FIG. 1, it can be confirmed that the low-temperature environment laser texturing device of the present invention can help form a precise texture while minimizing thermal effects during processing.

[0117] FIG. 2 is an example of a texture produced using low-temperature laser texturing according to the present invention. Referring to FIG. 2, the left drawing shows a plan view of a processed surface, and it can be seen that circular textures arranged at regular intervals are formed. The distance between the circular textures is indicated by 6, and the distance between the centers of the textures is indicated by reference numeral 7. The right drawing shows a cross-sectional view of the same surface viewed from the side, and the depth of the texture formed through laser processing is indicated by reference numeral 8.

[0118] Figure 3 shows the result of texturing a steel surface under conditions of room temperature and 6 W laser power. Referring to Figure 3, the left drawing is an optical microscope image of the steel surface, and it can be seen that a circular pattern texture has been formed. A cross-sectional analysis is added at the bottom, and the right drawing displays the cross-sectional height profile of the texture as a graph. In the graph, protrusions and irregularities that repeat at a specific period can be observed. Through Figure 3, it can be seen that while a consistent texture can be formed using 6 W laser power under room temperature conditions, there is a possibility of fine processing defects, and the quality of the texture may vary depending on the laser irradiation conditions.

[0119] Figure 4 shows the result of texturing a steel surface at room temperature under 2 W laser power conditions. Referring to Figure 4, in the optical microscope image on the left side, a circular pattern texture is formed, but compared to Figure 3, it can be seen that the surface processing state may be relatively non-uniform. Looking at the cross-sectional height profile on the right side, the protrusions and irregularities of the texture are inconsistent, and it shows that it may be difficult to secure a sufficient processing depth due to the low laser irradiation energy. Through Figure 4, it can be confirmed that when using a low laser power of 2 W at room temperature, texture formation may be incomplete, and there is a high possibility that the depth and shape will not be uniform.

[0120] Figure 5 shows the result of texturing a steel surface according to the present invention under low temperature and 6 W laser power conditions. Referring to Figure 5, it can be seen that the arrangement of circular textures formed in the left drawing is formed relatively precisely. Looking at the cross-sectional height profile in the right drawing, the depth and shape of the texture are maintained at a constant period, and it appears that fine non-uniformity is reduced compared to room temperature conditions. This demonstrates that when laser texturing is performed in a low-temperature environment, thermal deformation of the surface is suppressed, making it possible to form a more uniform pattern. Through Figure 5, it can be confirmed that applying 6 W laser power in a low-temperature environment allows the shape of the texture to be maintained more precisely, and increases the likelihood of securing uniform depth and shape compared to room temperature conditions. Furthermore, it suggests that fine surface damage can be reduced as the thermal influence during processing is decreased.

[0121] Figure 6 shows the result of texturing a steel surface according to the present invention under low temperature and 2 W laser power conditions. Referring to Figure 6, it can be seen that a circular texture is formed in the left drawing, and a more uniform pattern appears compared to the room temperature and 2 W conditions of Figure 4. Looking at the cross-sectional height profile in the right drawing, it can be seen that the change in depth of the texture is relatively constant and that fine surface deformation is reduced. This indicates that applying low laser power in a low-temperature environment may improve the uniformity of the texture. Through Figure 6, it can be confirmed that applying 2 W laser power in a low-temperature environment may be advantageous for maintaining surface uniformity while using low irradiation energy, and that more precise pattern formation may be possible compared to room temperature.

[0122] Although the present invention has been described above with reference to preferred embodiments, those skilled in the art will understand that various modifications and changes can be made to the invention without departing from the spirit and scope of the invention as set forth in the following claims. Explanation of the symbols

[0123] 1: Laser oscillator 2: Laser Convergence Lens 3: Sample for texture processing 4: Low temperature plate 5: Clamp for securing samples 6: Texture size 7: Texture spacing 8: Texture depth

Claims

Claim 1 A laser texturing device comprising: a laser oscillator that generates a laser toward the texturing target; a target receiving portion in which the texturing target can be received; and a cooling portion formed integrally with or separately from the target receiving portion and capable of cooling the texturing target received in the target receiving portion. Claim 2 A laser texturing device according to claim 1, wherein the cooling unit cools the texturing target to -20°C or lower. Claim 3 A laser texturing device according to paragraph 2, wherein the cooling unit cools the texturing target to -40 to -20 ℃. Claim 4 A laser texturing device according to claim 1, further comprising a focusing lens that focuses a laser irradiated from the laser oscillator. Claim 5 In claim 1, the laser texturing device, wherein the laser oscillator generates a laser with an output of 2 to 6 W. Claim 6 In claim 5, the laser texturing device, wherein the laser oscillator generates a laser at a frequency of 3 to 8 kHz. Claim 7 In claim 1, the laser texturing device forms a micro-sized texture. Claim 8 A laser texturing device according to claim 7, wherein the micro-sized texture is 10 to 500 μm. Claim 9 A laser texturing method comprising: a first step of cooling the texturing target and maintaining the cooled state; and a second step of generating a laser through a laser oscillator toward the texturing target to perform laser texturing. Claim 10 A laser texturing method according to claim 9, wherein the cooling of the first step is cooled to -20°C or lower. Claim 11 In claim 9, the laser texturing method wherein the laser oscillator generates a laser with an output of 2 to 6 W. Claim 12 In claim 11, the laser texturing method wherein the laser oscillator generates a laser at a frequency of 3 to 8 kHz. Claim 13 In claim 9, the laser texturing is a laser texturing method that forms a micro-sized texture. Claim 14 In claim 13, a laser texturing method wherein the micro-sized texture is formed to a size of 10 to 500 μm. Claim 15 A machine part having a texture formed on its surface by performing laser texturing on the surface through the laser texturing method according to claim 9. Claim 16 In claim 15, the texture formed on the machine part has a size of 10 to 500 μm, and the burr height of each texture is 30 μm or less.

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